class Carro():
    consumo = None
    combustivel = None
    
    def __init__(self, consumo, combustivel = 0):
        self.consumo = consumo
        self.combustivel = combustivel
        
    def abastecer (self, combustivel):
        self.combustivel = combustivel
        return  
    
    def andar (self, distancia):
        distanciaPercorrida = distancia
        return
    
    def medirGasolina(self, combustivel, distancia, consumo):
        total = combustivel - (distancia / consumo)        
        print total
        
consumo = input()
combustivel = input()
distancia = input()


fusca = Carro(consumo)

fusca.abastecer(combustivel)

fusca.andar(distancia)

fusca.medirGasolina(combustivel, distancia, consumo)